As a conventional plasma processing apparatus, use has been made of an apparatus as described in Patent Document 1. As described in Patent Document 1, this plasma processing apparatus comprises a radial line slot antenna adapted to radiate a microwave into a process chamber, a phase delay plate adapted to compress the wavelength of the microwave radiated from the antenna, a cover plate disposed at an interval from the phase delay plate, and a dielectric member disposed immediately below the cover plate. Further, a construction having a number of gas outlets is disposed under the dielectric member at an interval therefrom.
A gas for plasma generation is supplied into a vacuum container. When the microwave is applied from the antenna in this state, a high-density plasma is generated in a space between the dielectric member and the construction. This plasma is introduced through the construction into a process space where a semiconductor wafer is processed. With such a configuration, a process gas ejected from the gas outlets of the construction is excited by the high-density plasma formed under the dielectric member.
In this case, a flange constituting the process container is formed with a plasma gas supply passage communicating with a plasma gas inlet provided in an outer wall of the process chamber. From the plasma gas inlet, the plasma excitation gas such as Ar or Kr is fed to the supply passage in the flange. Further, the excitation gas is introduced into the process chamber through the supply passage and a gas outlet of the flange.
In the foregoing plasma processing apparatus having the radial line slot antenna, the uniform high-density plasma is formed in the space immediately below the dielectric member.
Patent Document 1:
Japanese Unexamined Patent Application Publication (JP-A) No. 2001-500327